1. Field of the Invention
This invention relates to a woven belt for a machine for producing web material, in particular forming mesh, including at least two woven layers with warp threads extending in a belt longitudinal direction and weft threads extending in a belt transverse direction, wherein a first of the woven layers provides a web material contact side and a second of the woven layers provides a machine contact side and the woven layers are joined together by tie warp threads. In addition this invention relates to a method with which such a woven belt can be manufactured.
2. Description of the Related Art
In the case of woven belts of the type used for example as forming meshes on machines for producing web material such as paper or paperboard, an elementary requirement is that there should be as little tendency as possible to marking in the web material to be produced. This means that the structure of the woven belt should impress itself as little as possible in the web material to be produced because such an impression of the structure, generally referred to as marking, impairs the quality of the produced web material.
Markings are produced above all when a very regular tie structure or weave structure exists in the woven belt. Hence there is a general endeavor to make the repeat lengths in both the warp direction and the weft direction, meaning in general the size of a warp/weft repeat, as large as possible. In this way it is possible to obtain a greater diversity of variation of the mutual tie points of warp threads and weft threads as well as an accordingly greater irregularity of said tie points.
What is needed in the art is a woven belt for a machine for producing web material and a method for manufacturing such a woven belt, by way of which an improved weave structure with a smaller tendency to marking is obtained.
The term “tendency to marking” is understood in this context to mean for example a line-shaped marking which extends for example in the warp or weft direction or in a diagonal direction thereto.